Former President Bill Clinton and Democratic presidential candidate Hillary Clinton's daughter announced on Twitter Saturday that she and her husband welcomed their second child.

"Marc and I are overwhelmed with gratitude and love as we celebrate the birth of our son, Aidan Clinton Mezvinsky," Chelsea, 36, wrote.

She and Marc, 38, are also parents to 1-and-a-half-year-old daughter Charlotte.

"We are overjoyed to be grandparents again with the arrival of our grandson, Aidan Clinton Mezvinsky, born on Saturday, June 18, 2016," Bill and Hillary said in a joint statement to E! News. "We are all over the moon as Chelsea and Marc welcome Charlotte's little brother to the world and grateful for our many blessings. Chelsea and Aidan are both doing well and enjoying this very special time together."

Throughout her pregnancy, she often helped campaign for her mother across the country and often attended rallies with her. Her most recent public appearance was last week, when she, Marc and Bill supported Hillary at a rally at the Duggal Greenhouse in Brooklyn, New York.